Tuesday, April 25, 2017

Featured Scientist: Meet Sennai!

Our annual surveys would not be possible without our wonderful collaborators from around the world. We'll dedicate several future blog posts to highlight these individuals, so that you can learn more about them, their research, and the valuable contributions they make to the survey. You can find previous posts here. Today we feature Sennai Habtes from the University of the Virgin Islands!

Sennai Habtes has been a longtime collaborator with the FORCES lab, since his days as a PhD student. We are always excited to get to sail with him each year! Sennai is a Research Assistant Professor of Biological Oceanography at the Center for Marine and Environmental Studies, University of the Virgin Islands.

"This year I am working with the scientists of the NOAA SEFSC, Dr. Dan Otis from the University of South Florida, and Dr. David Lindo from the City University of New York, to understand how physical oceanographic processes affect larval dispersal around spawning periods. We are particularly interested in two phenomena: where do grouper larvae go after they are spawned, and how the oceanographic conditions surrounding high biological productivity areas in the USVI and Puerto Rico have an impact. Myctoperca venenosa, or the Yellowfin Grouper, spawn approximately 8-10 days after the full moon from January until April, at spawning aggregations sites along the shelf surrounding the USVI (primarily along the Gramanik Bank, on the South Drop). Although we routinely sample for larval fish during the times of year when grouper are actively spawning around the USVI, we have very little luck catching these larvae. We believe this may because they target zones with particular currents that transport the larvae below the surface. During this cruise we are using specialized nets called a MOCNESS (Multiple Openning and Closing Net Environmental Sampling System) to sample the area surrounding the spawning aggregations. This will allow us to determine where in the water column these larvae are transported.

Grouper larva, ~5mm length
Photo credit: FORCES Lab
"Additionally, we are targeting Lang Bank on St. Croix, to determine how oceanographic conditions, which support a high biological region there, influence the transport of larval fish. Along with our traditional measurements of oceanographic conditions, and net sampling of zooplankton and ichthyoplankton (larval fish) we are also using satellite imagery to identify interesting features that may help in either transporting the larvae faster or retaining them in coastal areas surrounding the USVI. These are two smaller studies that we have implemented in this years cruise to help understand how the coastal oceanography around the USVI and PR affect larval recruitment (addition of new fish into adult populations) and connectivity (transport, ultimately allowing for better management of marine fish populations in the Eastern Caribbean."

Satellite image shows the oceanography of the US Virgin Islands, with tracks of the drifters deployed on NF-17-03.
Image courtesy of Dr. Dan Otis - Institute for Marine Remote Sensing USF-CMS

For more on Sennai’s research see his faculty webpage at UVI: http://www.uvi.edu/directory/profiles/staff/habtes-sennai-y.aspx
or this recent news post from the team at the VI-EPSCoR program about Sennai’s background and his research: https://www.viepscor.org/news/2017/4/12/drhabtes

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